>I'm having an RF issue only when I try to load my Hunter 2000C on 20m.
You didn't say what kind of antenna or its proximity to your shack. How
is it fed? Some antennas put lots of RF in the shack, depending on what
kind of antenna and where it is.
On Mon, 25 Jan 2010 15:09:07 -0800, Bill, W6WRT wrote:
>1. If the ground wire you have is one that runs from your chassis
>outside to an earth ground, remove it. You don't need it and it may
>actually be acting as an antenna.
WRONG! There should ALWAYS be good bonds between the chassis of all
equipment in the shack, the green wire in the power system in your
shack, and the ground electrode system for your home. AND, all ground
electrodes (rods, cold water, building steel, arrestor grounds for
telco and CATV) must also be bonded together. To do otherwise is UNSAFE
and ILLEGAL. Further, having this connection there are not is a SAFETY
issue. It should not FIX an RFI problem, nor should it CAUSE an RFI
problem -- unless, of course, something is badly wrong with your power
wiring.
>2. Be sure your transceiver, amplifier and computer are physically
>close together and their grounds bonded together with a short wire.
YES! But what should be bonded is their chassis.
>DO NOT run a ground wire outside to the earth.
WRONG. See above.
>3. If the RFI problem is still present, are you using an unbalanced
>antenna without a balun? If so, install a balun at the antenna.
A robust common mode choke at the antenna can prevent coupling of RF
down the transmission line, but I don't suspect that as the cause.
A more likely cause is common mode RF current picked up on one or more
cables connected to your rig or power amp that is exciting a "pin 1
problem" in either the rig or the amp.
There's a tutorial on RFI on my website.
http://audiosystemsgroup.com/RFI-Ham.pdf
BTW -- I'd also like to know what a 280 ohm ground is. :) FWIW, the
earth is generally pretty lossy, and it's not easy to achieve an
impedance to earth below 25 ohms. (Nor is it easy to measure that
impedance).
73,
Jim K9YC
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